Embodiments are provided for protecting boot block space in a NAND memory device connected to a host device via an SPI interface. One such method includes programming a boot block password into the NAND memory device such that the host device is required to provide the boot block password in order to access the boot block space. A counter may be provided to track the number of times the host device provides an incorrect password, permanently locking the boot block space if the counter reaches a predetermined value. A further method includes associating each of various areas of the boot block space with at least one write lock bit, setting the write lock bit to a lock enable or lock disable value, and locking or unlocking an area of the boot block space depending on the value of its associated write lock bit. Areas of the boot block space may include a single boot block page, a single boot block, or a plurality of boot blocks.